The
Positive Benefits of Urban and Forestin
General to the SurroundingHuman
Community

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The items listed
here are just a sampling of an ever growing body of evidence that details
our need (and our children's need), that there be a significant presence
in our Urban settings and Cities by nature, to ensure our good health as
well as other cost effective benefits. Not all the web-sites
and papers have been reviewed or even found but are listed as they could
be useful to someone else. This list is far from a complete on the
subject noted but does provide a starting point and some understanding
in how to search further.

The papers
by John F. Dwyer are very useful & understandable in the non-timber
values/uses of a forest, as they touch on elements like - Social Dimensions,
Real Estate Values & Trees or Forests, Urban Hydrology, Medical
Benefits (just looking at a forest can improve your health and help
heal you!), Local Economic Development, the Sensory Dimensions of
Trees, The Symbolic Values of Trees, Trees as Religious Symbols, Psychological,
Human Roots in the Forest/Savanna and even - Fear of the Forest.
Along with the usual - Air Quality, Energy and Carbon Dioxide Conservation,
etc.

Abstract. With effective planning and management,
urban trees and forests will provide a wide range of important benefits
to urbanites. These include a more pleasant healthful and comfortable
environment to live, work, and play in, savings in the costs of providing
a wide range of urban services and substantial improvements in individual
and community wellbeing. Urban forestry plans should begin win consideration
of the contribution that trees and forests can make to people's needs.
Planning and management efforts should focus on how the forest can best
meet those needs. Past planning and management efforts have not been
as effective as they might have been because planners and managers have
underestimated the potential benefits that urban trees and forests can
provide, and have not understood the planning and managemerit efforts needed
to provide those benefits, particularly the linkages between benefits and
characteristics of the urban forest and its management.

Urban forests are a significant and increasingly
valuable component of the urban environment. However, with the limited
information on the benefits and costs of urban trees and forests currently
available to decision makers, management of these valuable assets continues
to be inadequate. Urban forest resources are declining in many cities.
and the resulting benefits are only a traction of what they could be.
In many instances costs are higher than necessary. We are just beginning
to learn about the extent and magnitudes of the many benefits and costs
associated with urban trees and forests, as well as the many ties between
urban forest resources and the quality of urban life. Research in
a number of areas suggests that we have vastly underestimated the many
ways that the urban forest touches the lives of urbanites, as well as the
deep significance that many people attach to trees. Furthermore,
we often lack reliable information on how to most effectively manage urban
forests to provide many of these benefits.

A sound understanding of the full range
of benefits and costs associated with urban forests, as well as how various
management practices, programs, and policies influence those benefits and
costs, is essential for action to enhance urban forests and the associated
well-being of urbanites. Benefits to consider include the goods and
services produced by urban trees and forests that are valuable to people.
These benefits vary over space and time according to changes in the urban
environment, its inhabitants, and their needs. Some benefits are
easily expressed in dollars or other numbers, while others are difficult
to quantity using such measures; but in the aggregate they are highly significant
to urbanites.

The long life of urban trees and forests
mandates planning with a view to future needs. Investments in the
planting and care of trees represent a long term commitment of scarce dollars,
and improper plantings can increase costs and reduce benefits. Therefore,
it is important to do it right and plan for future management. The
effectiveness of urban trees and forests in providing benefits to people
depends on their species composition, diversity, age, and location with
respect to people and other elements in the landscape. An ecosystem
approach that recognizes people as the central component offers the best
means to assess the complex interactions between urban trees and forests
and the well-being of urbanites, linking management actions with their
effects on urban forests and the associated benefits and costs.

The following discussion begins with the
influence of urban trees and forests on the physical and biological environment
and continues with the socio-economic importance of urban trees and the
environments that they create.

Physical/Biological Environment and Processes

Urban and community forests can strongly
influence the physical/biological environment and mitigate many impacts
of urban development by moderating climate, conserving energy, carbon dioxide,
and water, improving air quality, controlling rainfall runoff and flooding,
lowering noise levels, harboring wildlife, and enhancing the attractiveness
of cities. These benefits may be partially offset by problems that
vegetation can pose such as pollen production, hydrocarbon emissions, green
waste disposal, water consumption, and displacement of native species by
aggressive exotics(15). Urban forests can be viewed as a "living
technology," a key component of the urban infrastructure that helps maintain
a healthy environment for urban dwellers.

Energy and carbon dioxide conservation.

Trees can contribute to energy conservation
because they help to reduce the cost of heating and cooling buildings.
Projections from computer simulations indicate that 100 million mature
trees in U.S. cities (three trees for every other single family home) could
reduce annual energy use by 30 billion kWh, saving about 2 billion dollars
in energy costs (1). Savings associated with avoided investment in
new power supplies could augment these savings considerably. Also
associated with this energy savings is a 9 million ton per year reduction
in carbon dioxide emissions from power plants. At present, U.S. urban
forests are estimated to store approximately 800 million tons of carbon,
nearly 5 percent of live tree carbon storage in all US forests (19).
Recent studies by scientists and energy utilities show that when the costs
of planting, watering, and maintaining trees are considered, tree planting
is a more cost-effective energy and carbon dioxide conservation strategy
than many other fuel-saving measures (13).

As with most urban forest benefits, energy
savings can only be realized through appropriate management strategies.
With poor management, important benefits can be lost and increased costs
incurred. For example, annual space air conditioning and heating
costs for a typical home in Madison, Wisconsin increase from $671 for an
energyefficient planting design, to $700 for no trees, to $769 for trees
that block winter sunlight and provide little summer shade (11).
Costs for water, pruning, removal, litter clean-up, pollen, healthrelated
problems, and liability can also offset benefits, particularly if the wrong
tree is planted in the wrong place.

Air quality.

Trees exchange gases with the atmosphere
and capture particulates that can be harmful to people. The rate
at which trees remove gaseous pollutants such as ozone, carbon monoxide,
and sulphur dioxide depends primarily on the amount of foliage, number
and condition of the stomata, and meteorological conditions. Results
from computer studies indicate that trees can reduce appreciably the amount
of ozone in polluted air. Pine trees in Los Angeles were projected
to remove from the atmosphere (under 400 meters) about 8% of the ozone
and decrease the concentration around the leaves by 49% (18).

Urban ozone concentrations go up with increases
in ambient temperatures. One study found that the incidence of smoggy
days increased 1% for each 10C increase in temperature (26). Because
urban forests can reduce summertime temperatures they provide another means
of improving air quality.

By extrapolating from studies for non-urban
forests we can infer that a mature urban tree can intercept up to 50 pounds
of particulates per year. Planting of 500,000 trees in Tucson was
projected to reduce air-borne particulates by 6,500 tons per year.
The annual implied value of particulate matter control was estimated at
$4.16 per tree per year on average or $1.5 million for all trees each year
(12).

Citizens spend millions of dollars annually
to control gaseous and particulate pollutants through programs for vehicle
inspection and maintenance, oxygenated fuels, rideshare, and street paving
and sweeping. To the extent that trees can control pollutants there
is potential for improved air quality and substantial cost savings.
Urban forests can be viewed as components of an overall strategy to restore
air quality in our cities. Improved air quality will enhance physical
and mental health, resulting in substantial savings in expenditures for
health care. Improvements in air quality also reduce the costs of
repairing damage to buildings, statuary, etc- that poor air quality causes.

Urban hydrology.

Urban forests can play an important role in urban
hydrologic processes by reducing the rate and volume of stormwater runoff,
flooding damage, stormwater treatment costs, and water quality problems.
Runoff estimates for an intensive storm event in Dayton, Ohio showed that
the existing tree canopy reduced potential runoff by 7% and a modest increase
in canopy cover would reduce runoff by nearly 12% (20). Runoff reductions
could be further enhanced by directing runoff to landscape plantings.

By reducing runoff, trees function like
retention/ detention structures that are essential to many communities.
Savings in stormwater management costs from trees in Tucson were calculated
at $0.18 per tree per year or $600,000 over 500,000 trees and 40 years
(12). Reduced runoff due to rainfall interception can also reduce
stormwater treatment costs in many communities.

Water use by landscape vegetation is an
important issue in arid and semi-arid regions where water resources are
increasingly scarce; but also in other areas where drought can bring about
restrictions on watering. We know that annual water costs can be
twice as great as cooling energy savings from shade for high water use
species such as mulberry (14). However, energy savings have the indirect
effect of conserving water at power plants. In Tucson, 16% of the
annual irrigation requirement for each tree was offset by water conserved
at the power plant due to energy savings provided by the tree.

Because of recent regulations by the Environmental
Protection Agency aimed at improving the quality of urban runoff and growing
interest in water conservation, these hydrologic benefits will increase
in importance over time.

Noise reduction.

Field tests have shown that properly designed
plantings of trees and shrubs significantly reduce noise. Wide belts of tall dense trees combined
with soft ground surfaces can reduce apparent loudness by 50% or more (4,17).
Noise reduction from plantings along roadsides in urbanized areas is often
limited due to narrow roadside planting space. Buffer plantings in
these circumstances are typically more effective at screening views than
reducing noise.

Ecological benefits.

Urban forests promote ecological stability
by providing habitat for wildlife, conserving soil, and enhancing biodiversity.
Although the value of these benefits is seldom quantified, they are important
to many urban dwellers and to the long term stability of urban ecosystems.
Surveys have found that most citydwellers enjoy and appreciate wildlife
in their day-to-day lives (25). To enhance wildlife habitat, numerous
communities have developed programs to preserve valuable existing natural
areas and to restore the habitat on degraded lands. For example,
restoration of urban riparian corridors and their linkages to surrounding
natural areas have facilitated the movement of wildlife and dispersal of
flora. Usually habitat creation and enhancement increases biodiversity
and complements many other beneficial functions of the urban forest (10).
Because of the growing environmental awareness and concern for quality
of life in our cities, ecological benefits such as these will increase
in significance over time. There can also be problems or costs associated
with urban wildlife, including damage to plants and structures, droppings,
threats to domestic pets, disease, etc.

Social Dimensions

All of the benefits associated with the
physical/ biological environment and processes discussed above have significant
implications for people who live in urban areas. We now turn our
attention to critical people/forest interactions.

Desirable environments.

The presence of urban trees and forests
can make the urban environment a more pleasant place to live, work, and
spend leisure time. Studies of urbanites' preferences and behavior
confirm the strong contribution that trees and forests make to the quality
of life in urban areas. Trees and forests are a prominent component
of the landscape in most urban areas. Urban forests provide significant
outdoor leisure/recreation opportunities for urbanites. Based on
nine visits per year to local parks per person, and $1.00 per visit in
value added by the presence of well managed urban forest resources, the
total contribution of urban trees and forests in park and recreation areas
to the value of recreation experiences provided in the USA could exceed
$2 billion (8). These are both conservative estimates based
on studies in the Midwest (6,7), and do not include benefits fromtrees on residential lots and other "non-designated" areas.

The Forest Preserve District of Cook County,
Illinois provides more than 40 million visits per year from a base of 66,000
acres of urban forests. In addition to parks and preserves, urban
greenways provide a wide range of recreational opportunities. Bicycle
trails in river corridors in the Chicago Metropolitan area support up to
5,000 bicycles per day passing a given point an a single trail. To
the extent that urban trees and forests increase the quality of the urban
environment and make spending leisure time there more attractive, there
will be substantial savings in fuel consumed because people will not drive
to distant recreation sites as often. At $1.25 per gallon, the savings
to individuals across the U.S. total $300 million per year if just one
gallon per individual is saved by reduced leisure trips. It would
seem that the potential savings in fuel costs from an urban environment
that is enhanced by well managed trees and forests might be five times
that amount or $1.5 billion per year (8). Reduced fuel consumption
would substantially reduce air pollution and related problems.

Medical.

Reduced stress and improved physical health
for urban residents have been associated with the presence of urban trees
and forests. Studies have shown that landscapes with trees and vegetation
produce more relaxed physiological states in humans than landscapes that
lack these natural features. Hospital patients with
window views of trees recover significantly faster and with fewer complications
than comparable patients without access to such views (27).
Future research will identify specific situations (e.g., urban commuting)
in which urban forests can offset stress, and measure the amount of stress
reduction that occurs. The benefits to public health from using trees
to reduce urban stress are potentially very significant. In addition,
cleaner air can be expected to improve health. There may be health-related
costs as well, such as allergies to plants, pollen, orassociated animals and insects.

Psychological.

Urban forest environments provide esthetic
surroundings, increased enjoyment of everyday life, and a greater sense
of meaningful connection between people and the natural environment.
Trees are among the most important features contributing to the esthetic
quality of residential streets and community parks (21). Perceptions
of esthetic quality and personal safety are very sensitive to features
of the urban forest such as number of trees per acre and view distance
(22). Park and arboretum visitors have reported that trees
and forests provide settings for significant emotional and spiritual experiences
(3,23,24). These experiences are extremely important in people's
lives, and can lead to a strong feeling of attachment to particular places
and trees (9). An improved understanding of the emotional and symbolic
meanings of trees will enable managers to provide the kind of settings
that contribute to a meaningful and satisfying sense of place in the urban
environment. Costs include fear of trees, forests, and associated
environments.

Real estate values.

The sales value of real estate reflects
the benefits that buyers attach to the attributes of that property, including
the trees and forest resource found on the property, along the street,
and in neighboring parks and greenways. An individual's willingness
to pay for a residential property is likely to reflect the value of benefits
that they expect from these forest environments, including opportunities
for leisure out in the yard or in the neighborhood, reduced heating and
cooling costs, privacy, and the lack of a need to construct fences or screens.
The variation in sales prices over a large number of residential properties
with different forest resources on the property and nearby canbe used to infer the willingness of users to pay for those urban
forest resources (2). These increases in property values are not
a separate category of value that is distinct from the goods and services
provided; but rather one means of reflecting or capturing the values of
the many important services that urban residents receive from urban forests.

The ties between trees and property values
provide an incentive for homeowners to invest in trees since increased
revenues can be received at the time of sale of that home (i.e., an advertisement
mentioning well landscaped yard, shaded patio, close to parks and bicycle
trails, and an energy efficient home).

Economic values of trees and forests that
are expressed as increased real estate values also produce direct economic
gains to local communities through property taxes. Consequently,
tree planting and tree care on public and private lands can be viewed as
an investment that achieves an annual return in property taxes. A
conservative estimate of a 5 percent increase in property values due to
trees and forests on residential properties (several studies suggest higher
values) represents $25 per year on a conservative property tax bill of
$500, and quickly adds up to $1.5 billion per year over the 62 million
single family detached housing units in the USA. A more realistic
estimate is two to three times that amount.

Parks and greenways have been associated
with increments in the value of nearby real estate (5,16). Some of
these increments have been substantial and it appears that parks with an"
open space character" add most to the value of near by real estate.
We have yet to identify the increments in real estate value associated
with urban forest resources in street corridors.

Residential properties are not the only
real estate that gains in value from urban trees and forests. Shopping
centers frequently landscape their surroundings in an effort to provide
a pleasing environment that will attract shoppers, thereby increasing the
value of businesses and the shopping center. While we are currently
unaware of research that documents the increased business and tax receipts
that are associated with such efforts, trees and forests may make an important
contribution to the economic vitality of these businesses, and the private
sector is currently making substantial investments in this area — far in
excess of what is required by local regulations. One neighborhood
shopping district in Chicago has concluded that planting trees along the
street in front of their establishments increased their business activity.
Similarly, employers invest in landscaping, beyond what is required, to
enhance worker productivity and morale. While there is currently
no research to document the increased worker productivity in such environments,
building owners are generally able to obtain higher rents for offices that
overlook well-landscaped areas.

In short, trees and forests can make a substantial
contribution to property tax revenues, thereby providing annual returns
on municipal investments in urban trees and forests. These benefits
are offset, in part, by the costs of managing the forests and repairing
damages that may be associated with them, such as disruption of sidewalks,
sewers, powerlines, etc,

Local economic development.

Urban forest resources also make a broad
contribution to the economic vitality of a city, neighborhood, or subdivision.
While this is particularly difficult to quantify, it is apparently no accident
that many cities and towns are named after trees and forests (i.e., Elmhurst
and Oak Park) as are subdivisions (i.e. Tall Timbers and Timber Trails)
and many areas strive to be designated as a “Tree City USA." Many neighborhoods
select tree planting as a community improvement project. Trees can
dominate the urban environment and contribute much to its character.
In the Chicago area, communities such as Evanston, Oak Park, and Elmhurst
are well known for their mature forest environments. Atlanta's large
investment in downtown tree plantings has paralleled an upswing in convention
business and contributed to its image of a progressive, livable city.

Community action programs that start with
trees and forests often spread to other aspects of the community and result
in substantial economic development. Often trees and forests on public
lands — and to some extent those on private lands as well — are significant
"common property" resources that contribute to the economic vitality of
an entire area. The substantial efforts that many communities undertake
to develop and enforce local ordinances and manage urban forest resources
attests to the substantial return that they expect from these investments.

Societal.

Stronger sense of community, empowerment
of inner city residents to improve neighborhood conditions, and promotion
of environmental responsibility and ethics can be attributed to involvement
in urban forestry efforts. Active involvement in tree-planting programs
has been shown to enhance a community's sense of social identity, self-esteem,
and territoriality, and it teaches residents that they can work together
to choose and control the condition of their environment. Community
tree planting programs can help alleviate some of the hardships of inner
city living, especially for low-income groups. Research on environmental
education is exploring ways of teaching children about their responsibility
in caring for trees, and can provide badly needed opportunities for inner
city children to experience nature. Researchers are examining how
such early experiences with nature influence the willingness to adopt an
environmental ethic later in life.

Summary and Conclusions

With effective planning and management,
urban trees and forests will provide a wide range of important benefits
to urbanites. These include a more pleasant, healthful, and comfortable
environment in which to live, work, and play, savings in the costs of providing
a wide range of urban services, and substantial improvements in individual
and community well-being.

Urban forests can enhance the city environment
by influencing temperature, wind, humidity, rainfall, soil erosion, flooding,
air quality, scenic quality, and plant and animal diversity. Each
of these influences has significant implications for the well-being of
urbanites. But there are also environmental problems that may be
associated with the urban forest, such as the generation of pollen, hydrocarbons,
and green waste; water and energy consumption; obscured views; and displacement
of native species of plants.

A well planned and managed urban forest
can reduce costs for heating and cooling, health care, driving to exurban
areas for recreation and leisure, stormwater management, and damage from
flooding, erosion, and polluted air. Substantial increases in revenues
can also be associated with urban trees and forests, including the sale
of real estate (individual gains), real estate and business taxes (government
gains), and tourism (individuals and government may gain). Costs
associated with urban forests include establishment and care of the forest;
repair of forest-induced damage to other parts of the urban infrastructure
(particularly sidewalks and utilities); blocked solar collectors, and foregone
opportunities for activities such as gardening and sports.

Many important benefits and costs of urban
forests that contribute significantly to the well-being of urbanites are
not easily reflected in dollars and cents. Psychological benefits
associated with urban forests include more pleasant environments for a
wide range of activities, improvements in the esthetic environment (sights,
sounds, smells), relief from stress (which can lead to improved physical
health), enhanced feelings and moods, increased enjoyment of everyday life,
and a stronger feeling of connection between people and their environment.
Psychological costs can include fears of crime, animals, insects, disease
(i.e., Lyme disease), darkness, and failing trees or limbs; and the displeasure
of messiness and clutter.

Benefits attributed to urban trees and forests
extend beyond individuals to society. Societal benefits include a
stronger sense of community, empowerment to improve neighborhood conditions,
promotion of environmental responsibility and ethics, and enhanced economic
development (business, commerce, employment). Societal costs include money
and other resources that must be diverted from other social programs.

The challenge faced by urban forest resource
managers and planners is to balance the many benefits and costs that are
associated with urban trees and forests. Lack of information about
the extent and magnitude of these benefits and the best approaches for
providing them often makes that task a very difficult one.

Urban forestry plans should begin with consideration
of the contribution that trees and forests can make to people's needs.
Planning and management efforts should focus on how the forest can best
meet those needs. Past planning and management efforts have not been
as effective as they might have been because planners and managers have
underestimated the potential benefits that urban trees and forests can
provide, and have not understood the planning and management efforts needed
to provide those benefits, particularly the linkages between benefits and
characteristics of the urban forest and its management.

Research continues to document new ways
in which trees and forests can benefit urbanites, as well as the magnitudes
of these benefits. The efforts of urbanites to protect and preserve
trees as well as their enthusiastic involvement in tree planting programs
reflects their high regard for urban forest benefits.

Urban trees and forests promise to be even
more consequential in the years ahead. Increasing interest in cost-effective
and "minimum impact" approaches for improving the quality of the urban
environment suggests that trees will play increasingly important roles
in efforts to enhance air quality and improve urban hydrologic processes.
Worldwide concern for "global warming" suggests increasing interest in
trees for sequestering carbon and reducing carbon dioxide emissions.
Associated concern for efficient use of energy resources will bring increasing
attention to trees as a means of reducing heating and cooling costs as
well as for encouraging urbanites to spend leisure time in the urban environment
rather than driving to more remote areas. As we learn more
about the functioning of the urban ecosystem and the role of trees and
forests in that system, it is likely that these resources will assume new
roles in efforts to manage the urban environment.

With increasing emphasis on improving the
quality of life for urbanites and in "wellness" programs overall, increasing
attention will be given to trees and forests as a means for enhancing the
quality of urban life. This is likely to include efforts aimed specifically
at stress reduction and improved public health. As we learn more
about the deep psychological ties between urbanites and trees and forests,
it is likely that urban trees and forests will assume new roles in efforts
to increase the quality of urban life.

As we learn more about the contribution
of trees and forests to the value of residential and commercial real estate
it is likely that owners will make increasing investments in their trees
and forests. Local governments and energy utilities will undertake
programs to encourage such efforts, due in part to the increased tax revenues
that will result, and to avoid energy costs.

Education regarding the planting and care
of appropriate tree species in desirable locations will be critical to
the long term cost-effectiveness of these programs.

With increased evidence of the boost that
trees and tree planting can give to local economic development and the
sense of community, more community organizations will become involved in
tree planting and tree care and tree and forest-related projects will be
increasingly sponsored as a means of enhancing community spirit and organization.
These projects will also be increasingly seen as a means of providing a
sense of empowerment of inner city residents to improve neighborhood conditions
and for promoting environmental responsibility and ethics!

4. Cook, D.I. 1978. Trees, solid barriers, and combinations: Alternatives for
noise control. pp. 330-339. In Hopkins. G. led. Proceedings of the National Urban
Forestry Conference, USDA Forest Service, State University of New York
College of Environmental Science and Forestry. Syracuse, NY.

5. Corrill, M., Lillydahl, J., and L. Single. 1978. The effects of greenbelts on residential property values:
some findings on the political economy of open space. Land Econ. 54:207-217.

15. McPherson, E.G. and R.A. Rowntree. 1991. The environmental benefits of urban forests. pp. 52-57. In A National Research Agenda for Urban Forestry in the 1990's. International Society of Arboriculture, Research Trust, Urbana
IL.

17. Reethof, G. and O.H. McDaniel. 1978. Acoustics and the urban forest. pp. 321-329. In Hopkins, G. led.) Proceedings of the National Urban Forestry
Conference, USDA Forest Service, State University of New York College
of Environmental Science and Forestry, Syracuse, NY.

Some
notes on the Economic value of conservation lands(Prepared
by Wildlife Fellowship)

There is a general misconception
that the only real benefits derived from the protection of natural areas
are habitat for wildlife and playgrounds for outdoor enthusiasts. As a
result, some taxpayers and elected officials question the need to spend
millions of dollars on preservation and even more money on long term management.
It has been difficult to overcome this mistaken belief due to the challenges
inherent in deriving accurate estimates of the direct economic benefits
which natural areas provide. Fortunately, we are beginning to see some
well documented research that provides some actual dollar amounts in a
format that can be applied almost anywhere to compare the cost of protecting
and managing natural areas with the very real cost savings that these areas
provide on an ongoing basis in perpetuity.

The World Resources Institute(1)
has completed a study entitled The Value of Conservation Easements:
The Importance of Protecting Nature and Open Space . This study provides
a summary of annual per acre ecosystem benefits for four categories of
land from a variety of independent studies. The resulting range of these
economic benefits are listed by land type (see attached). By using the
lowest estimates for each category, and an approximation of the acreage
of each land type protected as of today (9/2003) by the ELAP Program in
Hillsborough County, we are able to provide an estimate of the minimum
Annual economic benefit of these lands:

This estimate of annual economic
benefit is based on a wide range of indices including the income derived
from additional outdoor recreational opportunities; the increased value
of residential properties located adjacent to conservation areas; the avoidance
of infrastructure costs including stormwater facilities; reduced flooding;
lower insurance costs; lower electric bills; and so on. It should be noted
that, if the average benefit estimates derived by the study had been used
in the above calculation, the total annual economic benefit would be $
896,000,000!

If that figure seems astronomical,
consider several recent stories in the Tampa Tribune highlighting the City
of Tampa s efforts to address stormwater infrastructure costs and to promote
its tree planting program. Excerpts from those articles include the
fact that the city is currently budgeting $10 million dollars annually
for its stormwater system, and needed an additional $8.5 million from the
special sales tax increase to address existing problems with the system(2).
Now the new mayor is calling for a special assessment to pay for the cost
of needed improvements. How much more would be needed for stormwater infrastructure
in both the city and county if an additional 40,000 acres was available
for development?

To quote from the article on the
tree planting program(3), According to the National
Arbor Day Foundation: One acre of forest absorbs 6 tons of carbon
dioxide and produces 4 tons of oxygen. And (A large city could)
save $4 billion each year in energy costs.

The obvious conclusion to be derived
from the above information is that, no matter what the actual income and
cost savings, the conservation of natural areas makes good sense from an
economic standpoint. Furthermore, for a minimal investment in responsible
environmental stewardship of those natural lands, to maintain or enhance
the habitat quality and provide compatible recreational opportunities,
the level of benefits to the community can be greatly increased.

1. World
Resources Institute. The Value of Conservation Easements: The Importance
of Protecting Nature and Open Space . West Hill Foundation for Nature,
December, 2002.

Frederick Law Olmsted, the granddaddy of American landscape architecture,
had little idea how prescient he was when he reported to the City of New
York in 1872 that the midtown Manhattan park he was busy creating would
serve as the "lungs of the city."

Today, the urban forests found within city parks across the country serve
not only as recreational and social centers but also as organic sponges
for various forms of pollution and as storehouses of carbon dioxide to
help offset global warming. Indeed, recent experiences in several U.S.
cities have shown Olmsted's metaphor for what is now Central Park to be
far more literal than figurative.

Each year in Chicago, for example, the urban tree canopy removes 15 metric
tons of carbon monoxide, 84 metric tons of sulfur dioxide, 89 metric tons
of nitrogen dioxide, 191 metric tons of ozone, and 212 metric tons of particulates,
according to David Nowak, project leader of the U.S. Forest Service's Urban
Forest Ecosystem Research Unit. Trees absorb these gaseous pollutants via
their leaf stomata (the tiny pores on leaves) and break them down into
less harmful molecules during photosynthesis.

Though scattered individual trees can absorb pollution, urban forests provide
the most bang for a city's buck. "Parks with higher proportions of their
area covered by healthy trees will provide the greatest impacts," said
Nowak. Chicago's urban forest canopy, which covers roughly 11 percent of
the city's total land, saves the municipal government more than $1 million
every year in what would otherwise be spent on traditional pollution mitigation
efforts, according to Nowak.

Urban forests also play an important role in sequestering carbon dioxide,
the potent greenhouse gas which is primarily to blame for global warming.
In Sacramento, Calif., a public-private partnership called Sacramento Shade
spearheaded the planting of more than 200,000 trees around the city in
the mid-1990s. In a study assessing Sacramento's bolstered tree cover,
Greg McPherson of the Western Center for Urban Forest Research found that
the region's urban forest removes more than 200,000 metric tons of carbon
dioxide from the atmosphere each year, saving taxpayers as much as $3 million
annually in pollution mitigation costs. "It's cheaper for [Sacramento]
to plant trees than to generate more electricity," McPherson concluded.

By absorbing and processing carbon dioxide, trees convert a potent greenhouse
gas into breathable oxygen and woody biomass. According to Eric Beckers
of the Texas Forest Service, tree_planting efforts in urban areas boost
this process, as city trees are "15 times more capable of reducing carbon
in the atmosphere" than rural trees. Gary Moll, a vice president at the
nonprofit group American Forests, asserts that trees are the "ultimate
urban multitaskers," performing the functions of air filter, sponge, humidifier,
heat shield, wind block, and carbon sink. "We want people to understand
that trees are an important part of the city infrastructure. There's a
hard part, and there's a green part, and we should be planning for both,"
said Moll. "It's just not good business to sacrifice trees."

Under Moll's supervision, American Forests is assessing the costs and benefits
of urban forests across the country. The group uses a combination of satellite
data, field surveys, computer modeling software, and geographic information
systems (GIS) technology to measure regional tree canopy and calculate
its dollar value. So far the organization has applied these analytical
techniques to urban forests in and around Denver, Houston, Seattle, Milwaukee,
Atlanta, Fort Lauderdale, and Washington, D.C. The group is expanding the
program to other cities this year.

Congress first recognized the importance of urban forests in 1978 with
the Cooperative Forestry Assistance Act, which provided funds to promote
the maintenance, expansion, and preservation of urban tree cover while
encouraging research and development of related technical skills at the
local level. The legislation also called for tree-planting to complement
existing urban forest and open space maintenance programs. The Urban and
Community Forestry Assistance Program of 1990 expanded aid to state foresters
and nonprofit organizations working to promote and expand urban forest
parklands. President Bush has pushed to increase annual propriations under
the program by more than $31 million per year.

Meanwhile, back in New York City, Olmsted's parks are working overtime
to decrease air pollution and sequester carbon dioxide while also providing
recreational opportunities and natural beauty for more than 8 million city
dwellers. Nowak estimates that the removal of air pollution by New York
City's existing tree cover saves taxpayers as much as $10 million each
year. Thanks to appropriations and encouragement from former Mayor Rudolph
Giuliani, the city's parks department has planted more than 15,000 trees
annually for the past three years.

Today, fully one-quarter of New York City's 28,000 acres of parks qualifies
as urban forestland. Fiona Watt, New York City's chief of forestry, expects
the tree canopy to "grow even more in coming years as the city government
is setting aside additional funds for aggressive tree-planting programs,
focusing not only on parks but also on sidewalks, traffic islands, and
other areas usually reserved for concrete." According to a recent study
by the U.S. Forest Service, New York City's five boroughs are home to more
than 5 million trees, covering approximately 17 percent of the public and
private land. Half of these trees are growing in parks.

Today New York City's crown jewel, Central Park, truly fulfills its designer's
vision. Every year, 20 million people — not to mention 275 of the United
States' 800 bird species — visit Central Park, in part because of the refreshing
air made possible by 26,000 trees across 136 acres of woodlands. "Disturbed
by the unhealthy condition of families living in cramped tenements, where
every breath was fouled with smoke from burning coal, Olmsted proposed
a new role for vegetation to relieve the stress of city life," writes Charles
A. Lewis, author of Green Nature/Human Nature: The Meaning of Plants in
Our Lives. "He anticipated the intense growth of metropolitan areas and
recognized that human benefit would accrue from setting aside land to remain
forever green. Parks would be 'lungs' for cities … where people could relax
and breathe air that had been cleansed and refreshed by trees."

Tschantz, B.A. and Sacamano, P.L..
1994.Municipal Tree Management in
the United States.Report produced by Davey Resource
Group, a Division of the Davey Tree Expert Company, and Communication Research
Associates, Inc.